I think that's a slightly naive statement to make. OK if you're only at WDW for a few days, and it's just you and friends/adult family... but we're taking a trip for 14 days with 3 under 5s. We can't just "stay at home" if someone goes out grumpy. If the kids have a meltdown (I'm expecting at least 3 a day

then we'll go back to the hotel, but that's all we can do really. And I strongly suspect that the patience of some of the adults will be tested, although I really hope that none of us will turn into the swearing ogres who scream at their kids like some of the people you see at the "happiest f***ing place on earth", LOL!
I must admit that after 8 days on my last trip I was overtired and in a foul mood

but as soon as I got to the parks it went away and I was happy me again

and that was without any kids!!